Abstract: Objective To evaluate the effect and risk of misoprostol for stimulating cervical maturity in women with post-term pregnancy negative for insulin-like growth factor binding protein-1 (IGFBP-1) in cervical secretion with modified Bishop score less than 3. Methods Seventy-one women with post-term pregnancy randomized into misoprostol group (n=37) and control group (n=34) received misoprostol placement at the posterior vaginal fornix and routine intravenous oxytocin infusion, respectively, to stimulate cervical maturity. Failure to respond to the treatment within the initial 24 h necessitated a repeated administration for no more than 3 times in all. Modified Bishop score was recorded and fetal heart monitored once every 24 h, and IGFBP-1 in the cervical secretion was detected at 24 and 48 h after drug administration. Results The misoprostol group showed better effect of cervical maturity stimulation than the control group (P<0.001), and the positivity rates of IGFBP-1 24 and 48 h after drug administration were significantly higher than that of the control group (P<0.01 and 0.001). The number of cases with indication for cesarean section was significant higher in the control group (P<0.001). There were no significant differences in postpartum hemorrhage, excessive uterine contraction, incidence of fecal contamination of the amniotic fluid or Apgar score of the newborn between the two groups (P>0.05). Conclusions Misoprostol is safe and effective for stimulating cervical maturity in women with post-term pregnancy who have modified Bishop score lower than 3 and are negative for IGPBF-1 in cervical secretion. Oxytocin is not advised for use in such gravida for stimulating cervical maturity. IGFBP-1 in cervical secretion may serve as an important index for evaluating the cervical maturity.